Civilians inspect the aftermath of a car bomb attack in the Husseiniyah area of northeastern Baghdad, Iraq, Thursday, April 25, 2013. A car bomb exploded after sunset on Wednesday, April 24, 2013 near a bus stop in Baghdad's mostly Shiite neighborhood of Husseiniyah, killing and wounding dozens of people, police said. (AP Photo/ Hadi Mizban)— AP

Civilians inspect the aftermath of a car bomb attack in the Husseiniyah area of northeastern Baghdad, Iraq, Thursday, April 25, 2013. A car bomb exploded after sunset on Wednesday, April 24, 2013 near a bus stop in Baghdad's mostly Shiite neighborhood of Husseiniyah, killing and wounding dozens of people, police said. (AP Photo/ Hadi Mizban)
/ AP

BAGHDAD 
Clashes spread to a key northern city and gunmen took over a town elsewhere in Iraq on Thursday, raising the death toll from three days of violence to more than 150 people as a wave of Sunni unrest intensified.

The turmoil is aggravating an already sour political situation between the Shiite-led government and Sunnis, who accuse Prime Minister Nouri al-Maliki's government of neglect and trying to disenfranchise their Muslim sect.

Al-Maliki appeared on national television appealing for calm amid fears the country is facing a return to full-scale sectarian fighting more than a year after U.S. troops withdrew.

The spreading violence came as Iraqi electoral officials announced preliminary results in local elections held Saturday - Iraq's first since U.S. troops left in December 2011.

With 87 percent of the ballots counted, al-Maliki's State of Law bloc was on track to win the most votes in eight of the 12 provinces participating in the vote, including Baghdad and the southern oil hub of Basra.

Anti-American cleric Muqtada al-Sadr's bloc was ahead in the southern Shiite province of Maysan, while a provincial level coalition was leading in the Shiite province of Najaf. Local coalitions also were ahead in the largely Sunni province of Salahuddin and the mixed province of Diyala.

The government last month delayed voting in two predominately Sunni provinces where anti-government protests have raged for months, citing security concerns.

The final results will offer a key measure of support for the country's political blocs and could boost the victors' chances heading into next year's parliamentary elections.

The election announcement was overshadowed, however, by the rising unrest.

Gunmen and police clashed for hours in several districts of the former Sunni insurgent stronghold of Mosul before security forces brought the situation under control Thursday afternoon.

Police said 31 militants and 10 police were killed in the fighting in Mosul, which has been one of the hardest areas to tame since bloodshed erupted after the U.S.-led invasion that ousted Saddam Hussein. Many residents remained holed up in their homes out of fear, although the city was largely quiet by evening.

Clashes also erupted late Thursday between gunmen and security forces in the former al-Qaida stronghold of Baqouba, prompting authorities to impose a curfew there and in the surrounding province, according to police.

The latest unrest began on Tuesday when fighting broke out in the northern town of Hawija during a security crackdown on a protest encampment. Three members of the Iraqi security force and at least 20 other people were killed. The government said gunmen fired on the security forces as they entered the camp to make arrests related to an earlier incident.

Iraqi Sunnis say they face discrimination, particularly in the application of a tough anti-terrorism law that they believe unfairly targets their sect, which formed the backbone of the insurgency but also was key to the downturn in violence after tribal leaders turned against al-Qaida in Iraq.

The government frequently carries out arrests in Sunni areas on charges of al-Qaida or Baathist ties. Protests escalated in December after the arrest of bodyguards assigned to Finance Minister Rafia al-Issawi, a Sunni, in late December.